The present invention relates in general to a musical instrument transducer, and pertains, more particularly, to a piezoelectric transducer used with a stringed musical instrument. Although the transducer or the present invention is adapted preferably for use with a violin of viola, it may also be used in association with other stringed musical instruments such as a banjo, mandolin or arch-top style guitar.
At the present time, the prior art shows a variety of electro-mechanical transducers employing piezoelectric materials such as described in U.S. Pat. No. 3,325,580 to Barcus et al, U.S. Pat. No. 4,491,051 to Barcus and U.S. Pat. No. 4,147,084 to Underwood. Most of these piezoelectric transducers are not completely effective in faithfully converting mechanical movements or vibrations into electrical output signals which precisely correspond to the character of the input vibrations. This lack of fidelity is primarily due to the nature of the mechanical coupling between the driving vibratile member and the piezoelectric material. Some of these prior art structures such as shown in U.S. Pat. No. 4,491,051 are also quite complex in construction and become quite expensive to fabricate.
It is noted that the Barcus et al U.S. Pat. No. 3,325,580 as well as the Underwood U.S. Pat. No. 4,147,084 pertain to the use of piezoelectric transducers in association with a violin instrument. Both of these patents teach the use of the transducer in association with the bridge of the instrument disposed in slots in the bridge. Both of these patents teach the insertion of the transducer in a fixed, force-fit manner. For example, the Barcus et al U.S. Pat. No. 3,325,580 makes mention of the fact that the piezoelectric plates are forcibly pressed or wedged in the slotted openings provided in the bridge. It has now been found that this type of mounting severely restricts normal bridge action. There is a tendency for the transducer to cause a muting of the instrument and also, with these prior transducer constructions there are sensing surfaces on both sides of the crystal that comprises the transducer and thus in addition to picking up string vibrations there is a tendency for the system to also undesirably pick up instrument body noise. This is overcome in accordance with the present invention by single side sensing on the crystal as to be described in further detail hereinafter.
Accordingly, it is an object of the present invention to provide an improved piezoelectric transducer particularly for use with a stringed musical instrument such as a violin or viola.
Another object of the present invention is to provide an improved transducer as in accordance with the preceding object and which provides for the faithful conversion of string vibrations into electrical signals that substantially exactly correspond with the character of such vibrations.
Still a further object of the present invention is to provide an improved musical instrument transducer as in accordance with the preceding objects and which is relatively simple in construction, can be readily fabricated and which can also be constructed relatively inexpensively.
Another object of the present invention is to provide an improved musical instrument transducer that is readily adapted for retrofit to existing stringed instruments without requiring any modification thereto.
A further object of the present invention is to provide an improved piezoelectric transducer that is constructed so as to distribute a force over the entire surface of the transducer crystal thus providing a higher output of voltage and improved sensitivity.
Still another object of the invention is to provide and improved musical instrument transducer that employs substantially only one side crystal sensing so as to minimize the pick-up of instrument body noise.
A further object of the present invention is to provide an improved musical instrument transducer that is installed on the instrument bridge but that yet does not interfere with normal bridge action during instrument string actuation.